Certain direct plating processes employ an aqueous alkaline solution to improve the conductivity of the film applied to electrically non-conductive surfaces to make them conductive. The direct plating processes to which this invention applies include those disclosed in U.S. Pat. No. 5,071,517 by Okabayoshi using microfine colloidal catalyst as disclosed in U.S. Pat. No. 4,933,010 also by Okabayoshi.
Workpieces previously processed through cleaner/conditioner and catalyst baths are contacted with the aqueous alkaline solution. The aqueous alkaline solution causes the conductive film applied from the catalyst bath to the non-conductive surfaces of the work pieces to exhibit lower resistance and higher conductivity. Because the aqueous alkaline solution improves or accelerates the performance of the catalyst, it is called an accelerator bath or accelerator solution.
In the normal course of treating workpieces, the efficiency of the accelerator bath deteriorates. The reduced efficiency is displayed by poorer ability to reduce resistance and simultaneously increase conductivity of the conductive film applied by the catalyst. This results in electroplated metal deposits that may incompletely cover the surface or be less uniform than desirable.
This invention improves the performance of deteriorated alkaline accelerator baths and prolongs their useful life.